我怎么知道用户在带有ncurses的控制台(Linux)中按了ESC键? [英] How can I know that the user hit the ESC key in a console with ncurses (Linux)?

问题描述

在检测我是否只是得到一个普通的 ESC 密钥(仅代码27)还是它是另一个 special 密钥(例如，发送的Arrow Up)时出现问题我三个字节: ESC [ A (27 91 65).

I have a problem in detecting whether I just got a plain ESC key (just code 27) or whether it was another special key such as an Arrow Up which sends me three bytes: ESC [ A (27 91 65).

现在，我了解了转义序列，我不了解的是，我怎么可能知道用户实际上键入了 ESC 而不是特殊键，因为它们都以27和 ESC开头只有27岁?

Now, I understand escape sequences, what I don't understand is how can I possibly know that the user actually typed ESC instead of a special key since both start with 27 and ESC is only 27?

请注意，我使用ncurses的wgetch()函数，如下所示:

Note that I use the wgetch() function from ncurses as in:

// initialization not shown initscr() should be enough for this test
while(!f_should_exit)
{
    int c(wgetch(f_win_input));

    // show codes of what the user types
    //
    printf("got [%d] ", c);
    // prints 27 when I hit ESC
    // prints 27 91 65 when I hit Arrow Up
}

我在vim中一直使用 ESC 和箭头键，因此我可以想象有一种简单的方法可以专门检测出按下了哪个键?！

I use the ESC and arrow keys all the time in vim so I would imagine that there is an easy way to specifically detect which key was pressed?!

推荐答案

这是X/Open Curses的标准功能. wgetch的手册页在 模式:

This is a standard feature of X/Open Curses. The manual page for wgetch discusses it in keypad mode:

当接收到可能是功能键开头的字符(在现代终端上，表示转义字符)，诅咒 设置一个计时器.如果序列的其余部分不在其中 在指定的时间，字符通过；否则， 返回功能键值.因此，许多终端在用户按下转义键与转义返回到程序之间会遇到延迟.

When a character that could be the beginning of a function key is received (which, on modern terminals, means an escape character), curses sets a timer. If the remainder of the sequence does not come in within the designated time, the character is passed through; otherwise, the function key value is returned. For this reason, many terminals experience a delay between the time a user presses the escape key and the escape is returned to the program.

默认情况下，给定窗口的keypad未设置为true，即库不执行此操作(如果需要功能键，则您的程序必须这样做):

By default, keypad is not set to true for a given window, i.e., the library does not do this (your program must, if you want function-keys):

keypad(win, TRUE);

在ncurses的输入选项手册页中描述了超时.要将转义符与功能(或光标或键盘键)区分开，可以使用notimeout，如

The timeouts are described in ncurses' input-options manual page. To distinguish an escape character from a function (or cursor, or keypad key), you could use notimeout, as mentioned in the discussion of nodelay:

在解释输入转义序列时，wgetch(3x)设置一个计时器 在等待下一个字符时.如果 notimeout(win, TRUE) 是 调用，则wgetch不会设置计时器. 超时的目的 是要区分从功能键接收到的序列，并且 用户键入的内容.

While interpreting an input escape sequence, wgetch(3x) sets a timer while waiting for the next character. If notimeout(win, TRUE) is called, then wgetch does not set a timer. The purpose of the timeout is to differentiate between sequences received from a function key and those typed by a user.

这篇关于我怎么知道用户在带有ncurses的控制台(Linux)中按了ESC键?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！